Understanding Header Loads
A header carries load across an opening. It may sit above a door, window, pass through, or garage bay. The header transfers gravity load to jack studs, posts, or masonry bearings. A clear estimate helps early planning. It also shows which input controls the result.
Load Path Basics
Most header work begins with tributary width. This width is the floor, roof, or wall area feeding the opening. Area load is measured in pounds per square foot. The calculator multiplies that area load by tributary width. This creates a line load along the header. Self weight is then added as a line load. Any beam, girder, or concentrated framing reaction can be entered as a point load.
What the Results Mean
The left and right reactions show support demand. They help size posts and check bearing. Maximum shear is the largest vertical force inside the member. Maximum moment is the main bending demand. Deflection shows expected sag under the entered service load. The limit ratio compares sag with a common span based target. A smaller ratio is stiffer. A warning appears when the calculated sag exceeds the selected limit.
Using the Chart
The chart plots demand along the span. Moment usually peaks near midspan for uniform loads. A point load shifts the peak toward its location. Shear starts high at one support. It changes across the span as loads are crossed. Deflection helps visualize service performance. The curve can show why a longer span increases sag quickly.
Practical Notes
This calculator supports planning, comparison, and documentation. It is not a stamped structural design. Real projects may involve load combinations, lateral loads, notches, holes, fasteners, bearing crushing, fire rules, and local code checks. Wood grade, steel section, composite action, and construction quality also matter. Use conservative loads when uncertain. Ask a qualified professional before changing structural framing. Keep a record of inputs, assumptions, charts, and exported reports.
Example Workflow
Start with service loads, not factored loads, when checking deflection. Then test factored loads for strength comparison. Change one input at a time. This reveals sensitivity. Long spans often control. Heavy point loads can control support reaction. Export the table before revising assumptions or sharing notes for later project review.